This proposal concerns the development and characterization of bioanalytical methods based primarily upon microcolumn separation techniques. The systems we are interested in are neurochemical in nature. This is a methods development oriented proposal. We plan to investigate the use of a carbon film electrode as an on-column electrochemical detector for microcolumn liquid separation schemes. This detector is extremely sensitive, should be applicable to any size column and application to capillary zone electrophoresis is feasible. The use of capillary zone electrophoresis for schemes involving neurochemically interesting compounds is planned with both laser fluorescence and electrochemical detection. Lastly, we propose to use electroosmotic flow to acquire extremely small volume samples and to "inject" these samples onto the capillary electrophoresis column. A similar scheme will be used to carry out in vivo perfusion experiments on rats. These experiments can be carried out with side-by-side capillaries drawn out to only a few microns in diamter.